﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Forest.Core {
    /// <summary>
    /// Base class for entities
    /// </summary>
    public abstract partial class BaseEntity {
        /// <summary>
        /// Gets or sets the entity identifier
        /// </summary>
        public virtual Guid Id { get; set; }

        public override bool Equals(object obj) {
            return Equals(obj as BaseEntity);
        }

        /// <summary>
        /// 短暂的？
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        private static bool IsTransient(BaseEntity obj) {
            return obj != null && Equals(obj.Id, default(int));
        }

        private Type GetUnproxiedType() {
            return GetType();
        }

        public virtual bool Equals(BaseEntity other) {
            if (other == null)
                return false;

            if (ReferenceEquals(this, other))
                return true;

            if (!IsTransient(this) &&
                !IsTransient(other) &&
                Equals(Id, other.Id)) {
                var otherType = other.GetUnproxiedType();
                var thisType = GetUnproxiedType();
                return thisType.IsAssignableFrom(otherType) ||
                        otherType.IsAssignableFrom(thisType);
            }

            return false;
        }

        public override int GetHashCode() {
            if (Equals(Id, default(int)))
                return base.GetHashCode();
            return Id.GetHashCode();
        }

        public static bool operator ==(BaseEntity x, BaseEntity y) {
            return Equals(x, y);
        }

        public static bool operator !=(BaseEntity x, BaseEntity y) {
            return !(x == y);
        }
        protected virtual void SetParent(dynamic child) {

        }
        protected virtual void SetParentToNull(dynamic child) {

        }

        protected void ChildCollectionSetter<T>(ICollection<T> collection, ICollection<T> newCollection) where T : class {
            if (CommonHelper.OneToManyCollectionWrapperEnabled) {
                collection.Clear();
                if (newCollection != null)
                    newCollection.ToList().ForEach(x => collection.Add(x));
            }
            else {
                collection = newCollection;
            }
        }


        protected ICollection<T> ChildCollectionGetter<T>(ref ICollection<T> collection, ref ICollection<T> wrappedCollection) where T : class {
            return ChildCollectionGetter(ref collection, ref wrappedCollection, SetParent, SetParentToNull);
        }

        protected ICollection<T> ChildCollectionGetter<T>(ref ICollection<T> collection, ref ICollection<T> wrappedCollection, Action<dynamic> setParent, Action<dynamic> setParentToNull) where T : class {
            if (CommonHelper.OneToManyCollectionWrapperEnabled)
                return wrappedCollection ?? (wrappedCollection = (collection ?? (collection = new List<T>())).SetupBeforeAndAfterActions(setParent, SetParentToNull));
            return collection ?? (collection = new List<T>());
        }
    }
}
